Raising system for vehicle seat

ABSTRACT

A raisable seat for a vehicle, comprising a frame for a seating portion, a rail, a raising mechanism suitable for moving the seating portion frame relative to the rail between a lowered position and a raised position, said raising mechanism comprising on each side of the seat at least one connecting rod, said connecting rod having a rod body with an upper end connected to the frame and a lower end connected to the rail, at least one connecting rod also comprising a protuberance extending from the lower end, the protuberance extending facing the rail, said connecting rod being adapted to deform, in the event of an impact, between a first state in which a gap separates the rail and the protuberance regardless of the position of the seating portion frame between the lowered position and the raised position, and a second state in which the protuberance is in contact at least locally with the rail.

TECHNICAL FIELD

The present invention relates to raisable seats for motor vehiclescomprising a frame for a seating portion, a longitudinal rail, a raisingmechanism suitable for moving the seating portion frame relative to thelongitudinal rail between a lowered position and a raised position, saidraising mechanism comprising on each side of the seat at least oneconnecting rod, said connecting rod having a rod body with an upper endconnected to the frame and a lower end connected to the rail.

BACKGROUND

In the known prior art, for example such as patent FR0702804, theconnecting rods of the raising mechanism have an elongate shape that issubstantially symmetrical with respect to an axis perpendicular to thedirection joining the two ends.

In the event of a frontal crash, it is common for the connecting rod tobe subjected to torsion about the direction of travel X of the vehicle.There is also a risk of vertical crushing along the Z axis.

It is therefore necessary to improve the raising mechanism in order tolimit the lateral displacement of the seat and prevent the seat fromcollapsing towards the door and/or the console, in case of a frontalcrash. It is also necessary to prevent a vertical collapse of the frontpart of the seat.

SUMMARY

To this end, in one aspect the invention proposes a raisable seat for amotor vehicle wherein at least one connecting rod also comprises aprotuberance extending from the lower end, the protuberance extendingfacing the longitudinal rail, said connecting rod being adapted todeform, in the event of an impact, between a first state in which a gapseparates the longitudinal rail and the protuberance regardless of theposition of the seating portion frame between the lowered position andthe raised position, and a second state in which the protuberance is incontact at least locally with the longitudinal rail.

By virtue of these arrangements, in the event of an impact, the planarcontact between the protuberance and the rail absorbs part of the force,limiting the deformation of the connecting rod about axis X and along Z.The gap reserved between the protuberance and the rail, during normaloperation, reduces friction and thus prevents premature wear of thesurface of the protuberance and the irritating noises associated withcontinuous friction.

In various embodiments of the invention, use may possibly be made of oneor more of the following arrangements:

-   -   the shape of the protuberance is adapted to enable planar        support of the protuberance on the longitudinal rail during        contact in the second state,    -   the protuberance extends continuously from the body of the        connecting rod with no discontinuity in the material,    -   the protuberance has a shape locally complementary to the shape        of the rail,    -   the longitudinal rail comprises a movable profile and a fixed        profile, the protuberance comprising a portion facing the fixed        profile,    -   the movable profile comprises a horizontal upper web and at        least one lateral wing extending substantially vertically        downwards from the horizontal upper web, and the fixed profile        comprises at least one horizontal wing extended by a hanging end        wall, said hanging end wall facing a lateral wing of the movable        profile, the protuberance extending substantially parallel to        and close to the horizontal wing of the fixed profile,    -   the protuberance comprises a first part facing the movable        profile and a second part facing the fixed profile,    -   the movable profile comprises a horizontal upper web and at        least one lateral wing extending substantially vertically        downwards from the horizontal upper web, the fixed profile        comprising at least one horizontal wing extended by a hanging        end wall, said hanging end wall facing a lateral wing of the        movable profile, the protuberance comprising a first portion        substantially parallel to and close to the horizontal upper web        of the movable profile, a second portion substantially parallel        to and close to said lateral wing of the movable profile, and a        third portion substantially parallel to and close to the        horizontal wing of the fixed profile,    -   the seat comprises a base mounted on the longitudinal rail, the        raising mechanism being atop the base, the lower end of the        connecting rod being connected to the base.    -   the base is connected to the connecting rod by a pin, the third        portion having an extension along the lower end of the body of        the connecting rod that is smaller than the first portion and        the second portion, the extension of the third portion along the        lower end of the body of the connecting rod corresponding to an        angular portion around the pin of between 60° and 120°,    -   the end of the third portion has the shape of an arc of a        circle,    -   the longitudinal rail comprises a movable profile and a fixed        profile, the movable profile comprising a horizontal upper web        and at least one lateral wing extending substantially vertically        downwards from the horizontal upper web, the fixed profile        comprising at least one horizontal wing extended by a hanging        end wall, said hanging end wall facing a lateral wing of the        movable profile, the protuberance being formed by a single        portion that is both substantially parallel to and close to the        lateral wing and substantially parallel to and close to the        horizontal wing,    -   the protuberance extends along only a portion of the lower end        of the body of the connecting rod,    -   a free end of the protuberance has a shape adapted to maintain a        substantially constant gap between said free end and the        longitudinal rail during the travel of the connecting rod to        move the seat between the lowered position and the raised        position, in the first state,    -   the connecting rod is a front connecting rod.    -   the seat comprises a rear connecting rod, the rear connecting        rod also comprising a protuberance extending from the lower end        of the rear connecting rod, the protuberance extending facing        the longitudinal rail.

BRIEF DESCRIPTION OF DRAWINGS

Other aspects, objects, and advantages of the invention will be apparentfrom reading the following description of one of its embodiments givenby way of non-limiting example, with the aid of the accompanyingdrawings in which:

FIGS. 1a and 1b are partial schematic views of a seat structurecomprising a raising mechanism, in the raised and lowered positionrespectively,

FIG. 2a is a partial schematic view of the device for driving theconnecting rods,

FIG. 2b shows a detail view of the device for driving a front connectingrod,

FIGS. 3a, 3b, and 3c are cross-sections of the front connecting rodmounted on the base between the rail and the seating portion frame inthree different embodiments,

FIGS. 4a and 4b are side views of the front connecting rod in the firstembodiment, respectively in the lowered position and raised position.

DETAILED DESCRIPTION

FIG. 1 shows a schematic and partial representation of a vehicle seatcomprising a seating portion with a frame 1, a backrest being mounted onthe seating portion, the entirety being mounted on a rail 2 via araising mechanism 4. In the present case, a base 3 is on top of the rail2, the raising mechanism 4 being mounted on the base 3. The base 3 issecured to the rail 2. The base 3 may be a separate part from the rail 2or may be formed integrally with the rail 2.

This raising mechanism 4 is designed to move the seating portion withrespect to the base in at least one substantially vertical direction Z.

This raising mechanism is obtained by means of connecting rods 4 a; 4 b.

For example, for each of said connecting rods, the lower end isconnected to the rail 2 and the upper end is connected to the frame 1 ofthe seating portion of the seat.

The seating portion frame 1 generally has a right side and a left sideof similar architectures; only one side is shown in FIG. 1, andtherefore there are other connecting rods between the seating portionand the rail on the side not shown, equivalent to the connecting rods 4a; 4 b represented.

A front connecting rod 4 a connects the rail 2 to a front part 1 a ofthe seating portion frame 1 and a rear connecting rod 4 b connects therail 2 to a rear part 1 p of the frame 1. More precisely, in theillustrated example, a front connecting rod 4 a connects the front part3 a of the base 3 (pivotable mounting on pin referenced 31) to a frontpart 1 a of the frame 1 of the seating portion (pivotable mounting onpin referenced 11), and a rear connecting rod 4 b connects the rear part3 p of the base 3 (pivotable mounting on pin referenced 32) to the rearpart 1 p of the frame 1 (pivotable mounting on pin referenced 12). Inthe example illustrated, the pivotable mountings of the first and secondconnecting rods 4 a; 4 b are all on pins parallel to the transverse axisY, which is perpendicular to the longitudinal axis X and perpendicularto the vertical axis Z.

The connecting rods 4 a, 4 b may be moved independently by respectivecontrol means or may be controlled simultaneously by synchronizedcontrol means or by a mechanical connection which can connect them.

When the front connecting rod 4 a is pivoted in a counterclockwisedirection by the raising mechanism 4, then the front part connected tothe seating portion is raised upwards; whereas conversely, when thefront connecting rod 4 a is pivoted in a clockwise direction, then thefront part of the seating portion is lowered towards the floor.Similarly, when the rear connecting rod 4 b is pivoted in thecounterclockwise direction, then the rear part of the seating portion israised upwards; while when the rear connecting rod 4 b is rotated in aclockwise direction, the rear part of the seating portion is loweredtowards the floor.

When controlling the system of connecting rods 4 a, 4 b, the seatingportion is moved substantially parallel to the floor, which is referredto as a “raising” movement as illustrated in FIGS. 1a (raised position)and 1 b (lowered position). Between the lowered and raised positions,the connecting rods 4 a, 4 b are pivoted by approximately 30 degrees inthe counterclockwise direction, which defines the path of the connectingrods between the lowered position and the raised position.

The front connecting rod 4 a (or rear connecting rod 4 b) is for exampleintegrally connected to a transverse bar extending along the transverseaxis Y and connecting the connecting rod represented to an equivalentconnecting rod arranged on the other side of the seating portionstructure (not shown).

As illustrated in FIGS. 2a and 2b , the front connecting rod 4 a is forexample integrally connected to a control plate 43 which is shown as ametal plate extending in a plane X, Z (detail of FIG. 2b ). This controlplate 43 is connected directly to the transverse bar and/or to theconnecting rod 4 a and comprises, on an end section of substantiallycircular shape, a toothed area 44 intended to engage with a drivingdevice, for example a motorized device 46, which comprises a pinion 45directly engaging with the aforementioned toothed area 44.

Preferably, such a driving device is provided only on one side of theframe 1 of the seating portion of the seat; the other side may not haveone. The pinion is arranged so as to rotate about an axis Asubstantially parallel to the transverse axis Y.

A protective housing 47 may be provided to partially or almostcompletely cover the pinion 45 with the exception of the area engagingwith the toothed section.

If appropriate, a second driving device similar to the first may beprovided for driving the rear connecting rod 4 b in a similar manner.

The base 3 is mounted so as to slide with respect to the floor of thevehicle by means of longitudinal rails 2 comprising a fixed profile 21fixed to the floor of the vehicle and a movable profile 22 integral tothe aforementioned base 3 and sliding in the longitudinal direction X onthe fixed profile 21. In particular, the base 3 may be made as one piecewith the movable profile 22 of the rail 2. The base 3 and the movableprofile 22 are then in the form of a single part.

According to the embodiment illustrated in FIGS. 1a, 1b, and 2a , thebase 3 extends along the longitudinal direction X between the front part3 a and the rear part 3 p. However, this embodiment is not limiting andthe base 3 may comprise front and rear parts separate from one another.

The fixed 21 and movable 22 profiles are for example of metal. Forexample, the fixed 21 and movable 22 profiles fit into one another todefine a hollow internal space. For example, the movable profile 22 is amale profile and the fixed profile 21 is a female profile.

As represented in FIG. 3a and by way of example, the movable profile 22may have a substantially U-shaped cross-section. The movable profile 22may comprise a horizontal upper web 220 fixed to the seating portion ofthe seat. The movable profile may further comprise two lateral wings 221which each extend substantially vertically downwards from the seatingportion. The fixed profile 21 may also have a U-shaped cross-section,with a horizontal lower web 210 fixed to the floor of the vehicle andextending parallel to the web of the movable profile, and two lateralwings 211 each extending substantially vertically upward from the lowerweb. At least one of the lateral wings 211 of the fixed profile extendsto form an inward trough having a substantially vertical hanging endwall 213, a horizontal wing 212 connecting the lateral wing and thehanging end wall.

The front connecting rod 4 a comprises a rod body 40 with asubstantially elongate shape. The rod body is substantially symmetricalwith respect to an axis perpendicular to the direction connecting thetwo ends of the connecting rod. The connecting rod 4 a is in particularslightly incurved within the plane in which it travels from the loweredposition to the raised position. As illustrated in FIGS. 4a and b, thefront connecting rod 4 a according to the invention has a protuberance 5extending from the lower end of the rod body 40. As a variant, the rearconnecting rod 4 b may also have a protuberance 5′ with for example thesame properties as those described below. This protuberance 5 is forexample formed by material continuous with the lower end 42 of the bodyof the front connecting rod 4 a. For example, the front connecting rod 4a is obtained by shaping a metal structural part.

The protuberance 5 extends facing the longitudinal rail 2. Moreparticularly, the protuberance 5 has a shape locally complementary tothe shape of the rail 2.

The protuberance 5 is shaped on the external side of the connecting rod,meaning the side opposite to the side of the connecting rod intended tobe positioned between the two lateral rails of the seat. Theprotuberance 5 is also shaped on the side near the center of thevehicle, or the external side of the vehicle which is opposite to theside near the center of the vehicle.

The protuberance 5 will advantageously bear against the fixed profile ofthe rail in each of the embodiments.

In a first embodiment, the protuberance 5 has three portions extendingsubstantially concentrically with respect to axis 31. A first portion 5a extends from the lower end 42 of the body of the connecting rod 40,along only a portion of the lower end 42. A second portion 5 b of thesame or less extent along the lower end 42 as the first portion 5 aextends from the first portion. A third portion 5 c of the same or lessextent as the second portion 5 b extends from the second portion 5 b. Inplane Y, Z, as illustrated in FIG. 3a , the set of three portions 5 a, 5b, 5 c thus forms two consecutive bends, forming a shape locallycomplementary to the shape of the longitudinal rail in cross-section inthe plane transverse to X.

In particular, the protuberance 5 comprises a first portionsubstantially parallel to the horizontal upper web of the movableprofile 22, a second portion substantially parallel to said lateral wingof the movable profile 22, and a third portion substantially parallel tothe horizontal wing of the fixed profile 21. The protuberance 5therefore has a shape that is locally substantially complementary to theshape of the rail 2, enabling planar support of the various portions ofthe protuberance 5 against the rail 2 when the connecting rod 4 a is incontact with the rail 2 in plane X, Z and in plane X, Y.

In plane X, Z, the end of the protuberance 5 also has a general shapeadapted to allow planar support of the end of the protuberance 5 againstthe rail 2 in the event of unusual stress (a crash) along Z, regardlessof the position of the connecting rod in its travel. The end of theprotuberance also has a shape adapted to maintain a gap between the endof the protuberance of the connecting rod 4 a and the rail 2, regardlessof the position of the connecting rod in its travel.

The end of the protuberance has in particular the shape of an arc of acircle about axis 31, which allows the end of the protuberance to beparallel to the rail regardless of the position of the connecting rod inits travel, and to maintain a substantially constant gap between theconnecting rod 4 a and the rail 2 along the entire travel of theconnecting rod 4 a.

In a second embodiment illustrated in FIG. 3b , the protuberance 5extends substantially parallel to and close to the horizontal wing 212of the fixed profile 21. The protuberance 5 has a shape locally andsubstantially complementary to the shape of the rail 2, allowing planarsupport of the protuberance 5 against the rail 2 when the connecting rod4 a is brought into contact with the rail 2 in plane X, Y.

In a third embodiment illustrated in FIG. 3c , the protuberance 5 isformed by a single portion that is both substantially parallel to andclose to the lateral wing (221) and substantially parallel to and closeto the horizontal wing. In this embodiment, the protuberance 5 will bethick, meaning that the protuberance will have a substantiallyrectangular cross-section in the section plane (Y, Z) having twoadjacent sides one extending parallel to the horizontal wing 212 and theother parallel to the lateral wing 221. The protuberance 5 therefore hasa shape locally and substantially complementary to the shape of the rail2, allowing planar support of the protuberance 5 against the rail 2 whenthe connecting rod 4 a is brought into contact with the rail 2 in planeX, Z and in plane X, Y.

The protuberance 5 extends along only a portion of the lower end 42 ofthe body 40 of the front connecting rod 4 a.

In particular, in the first embodiment, the extent of the protuberance 5decreases continuously from the first portion 5 a to the second portion5 b, and then from the second portion 5 b to the third portion 5 c.

In particular, the third portion 5 c has an extension along the lowerend 42 of the body 40 of the front connecting rod 4 a that is strictlysmaller than those of the second portion 5 b or the first portion 5 a,the decreased size forming a “step” between the two portions. Theextension of the third portion 5 c along the lower end 42 of the body 40of the front connecting rod 4 a corresponds to an angular portion aroundthe pin 31 that is between 60° and 120°.

In the “normal” first state of operation of the raising mechanism, a gapis maintained between the longitudinal rail 2 and the protuberance 5,and this remains so throughout the travel of the connecting rod 4 arelative to the rail 2.

In the case of a frontal impact, in the second state, the connecting rod4 a tends to deform. The protuberance 5 is pressed against the rail 2,which limits the possible movements of the connecting rod 4 a around Xand along Z.

In the first embodiment, the first portion 5 a comes into planar contactwith the upper web 220, or the second portion 5 b comes into planarcontact with the lateral wing 221 of the movable profile 22, or thethird portion 5 c comes into planar contact with the horizontal wing 212of the fixed profile 21.

Thus, the contact between the first portion 5 a and the upper web 220limits the vertical collapse of the seat, meaning of the frame onto thebase. The contact between the third portion 5 c and the horizontal wing212 has the same effect. The contact between the second portion 5 b andthe lateral wing 221 of the movable profile 22 absorbs a portion of thetorsional torque about axis X generated by a frontal impact, thuslimiting the lateral buckling of the seat.

1. Raisable seat for a motor vehicle, comprising: a frame for a seatingportion, a longitudinal rail, a raising mechanism suitable for movingthe seating portion frame relative to the longitudinal rail between alowered position and a raised position, said raising mechanismcomprising, on each side of the seat, one connecting rod, saidconnecting rod having a rod body with an upper end connected to theframe and a lower end connected to the longitudinal rail, wherein: saidconnecting rod also comprises a protuberance extending from the lowerend, the protuberance extending facing the longitudinal rail, saidconnecting rod being adapted to deform, in the event of an impact,between a first state in which a gap separates the longitudinal rail andthe protuberance, regardless of the position of the seating portionframe between the lowered position and the raised position, and a secondstate in which the protuberance is in contact locally with thelongitudinal rail.
 2. Seat for motor vehicle according to claim 1,wherein the shape of the protuberance is adapted to enable planarsupport of the protuberance on the longitudinal rail during contact inthe second state.
 3. Seat for motor vehicle according to claim 1,wherein the protuberance extends continuously from the body of theconnecting rod with no discontinuity in the material.
 4. Seat for motorvehicle according to claim 1, wherein the protuberance has a shapelocally complementary to the shape of the rail.
 5. Seat for motorvehicle according to claim 1, wherein the longitudinal rail comprises amovable profile and a fixed profile, the protuberance comprising aportion facing the fixed profile.
 6. Seat for motor vehicle according toclaim 5, wherein: the movable profile comprises a horizontal upper weband one lateral wing extending vertically downwards from the horizontalupper web, the fixed profile comprises one horizontal wing extended by ahanging end wall, said hanging end wall facing a lateral wing of themovable profile, the protuberance extends parallel to and close to thehorizontal wing of the fixed profile.
 7. Seat for motor vehicleaccording to claim 1, wherein the protuberance comprises a first partfacing the movable profile and a second part facing the fixed profile.8. Seat for motor vehicle according to claim 7, wherein: the movableprofile comprises a horizontal upper web and one lateral wing extendingvertically downwards from the horizontal upper web, the fixed profilecomprises one horizontal wing extended by a hanging end wall, saidhanging end wall facing a lateral wing of the movable profile, theprotuberance comprises a first portion parallel to and close to thehorizontal upper web of the movable profile, a second portion parallelto and close to said lateral wing of the movable profile, and a thirdportion parallel to and close to the horizontal wing of the fixedprofile.
 9. Seat for motor vehicle according to claim 1, comprising abase atop the longitudinal rail, the raising mechanism being mounted onthe base, the lower end of the connecting rod being connected to thebase.
 10. Seat for motor vehicle according to claim 9, wherein the baseis connected to the connecting rod by a pin, the third portion having anextension along the lower end of the body of the connecting rod that issmaller than the first portion and the second portion, the extension ofthe third portion along the lower end of the body of the connecting rodcorresponding to an angular portion around the pin of between 60° and120°.
 11. Seat for motor vehicle according to claim 9, wherein the endof the third portion has the shape of an arc of a circle.
 12. Seat formotor vehicle according to claim 1, wherein the longitudinal railcomprises a movable profile and a fixed profile, the movable profilecomprising a horizontal upper web and one lateral wing extendingvertically downwards from the horizontal upper web, the fixed profilecomprising one horizontal wing extended by a hanging end wall, saidhanging end wall facing a lateral wing of the movable profile, theprotuberance being formed by a single portion that is both parallel toand close to the lateral wing and parallel to and close to thehorizontal wing.
 13. Seat for motor vehicle according to claim 1,wherein the protuberance extends along only a portion of the lower endof the body of the connecting rod.
 14. Seat for motor vehicle accordingto claim 1, wherein a free end of the protuberance has a shape adaptedto maintain a constant gap between said free end and the longitudinalrail during the travel of the connecting rod to move the seat betweenthe lowered position and the raised position, in the first state. 15.Seat for motor vehicle according to claim 1, wherein the connecting rodis a front connecting rod.
 16. Seat for motor vehicle according to claim15, comprising a rear connecting rod, the rear connecting rod alsocomprising a protuberance extending from the lower end of the rearconnecting rod, the protuberance extending facing the longitudinal rail.